I was having a problem with the throttle position sensor code along with emissions and the AWD light coming on, particularly after a car wash or when it rained. It didn't come on right away, but after the car had was shut down and restarted. It would go into limp mode and had to be towed or let sit without the battery cable until the code cleared.

For troubleshooting, I replaced the battery, downstream bank 2 O2 sensor and throttle position sensor (gas pedal).

None of these fixed the problem. I decided to swap the Electronic throttle control system (ETCS) control relay (10) with the Power Window Relay (8). Both of these are 39794-SDA-A03 Omron. These are both under the driver's side console.

This has solved the problem so far. It appears these relays can be semi-functional and will not alert a failure. I have ordered a new one and will only use the OEM relay in case this one causing the problem was a knock off.

Anyway, just thought I would share because this could be a costly troubleshooting process. Attached is the relay diagram. I will update if the status changes.

 

Thank you for sharing as you pointed out it may be helpful for others.

 

Went through a car wash with engine running and the lights came back on. It doesn't come on right away. After you shut down and leave the car for a while and then it comes on at the next start.

The ETCS control relay is ok.

Any ideas? Thanks!

 

Codes are P0641 sensor reference Voltage A - No idea?
PO453 Evap pressure switch high - removed gas cap. didn't clear
P2138 Throttle position sensor - already replaced with OEM

 

One thing to notice if this happens is that there will be a P068A code for the Engine DTC power relay de energized performance too early.

So, I switched the Omron relay with one that was not used before in that spot. I was able to clear the code and back to normal.

My conclusion at this point is that once these Omron relays are affected in the ETCS position, you cannot reuse it there. Have some spares on hand and if the emissions light comes on, replace that relay with a new one. Also, only go through car washes with the engine off.

 

Give this a read for P0641: https://www.autocodes.com/p0641_acura.html

 

Thank you. I think that when the Omron relay shuts down early, the other lights are triggered. I'm wondering if you can put more amps on that relay. Maybe bump it up a bit so they don't fry so easily.

 

Update on this. Happened again. I decided to run water down the windshield drain on the driver's side. Full bore garden hose. Looked by the fuse box under the driver's panel. There was a bit of water. Looks like I need to open the wheel well and patch a hole or two. Will update on the progress.

 

There are two hotspots for this issue. One is on the side of the driver's windshield. The water runs down into the cabin in the spaces. Also on the firewall there is a cluster of wires running into the cabin. I sprayed both these areas with spray foam insulation (any brand) and the leaks have stopped.

I have been a believer in Honda and its products. I have two cars and a motorcycle bought on reputation alone. But seriously, how do you not recall cars for this issue and spray with a $10 can of foam? I spent $700 at the dealer for them not to find this problem. I honestly am disheartened.

 

i'm glad you were able to find a solution and thank you for sharing. i have a 2017 RDX Tech AWD and a car wash subscription and never had the issue you described. I'm assuming you bought this vehicle new and the windshield has never been replaced?

 

I bought it used a year ago. After five AAA tows and $700 at Acura with no luck, I just had to fix this somehow.

The windshield is likely stock since it says Acura and a replacement would likely be aftermarket, I.e. Safelight et al.

I took off the front fender and some trim pieces. There are literally diapers on some of the panels to absorb water. This implies Honda knew about this as a problem. Makes you wonder. Maybe the factory forgot a diaper on mine.

One kudo to Honda is that the electrical system is pretty bulletproof. It took a lot of water and would only blow the Omron relay. Most other cars would have likely fried.

At least it’s fixed. 🤞

 

OMG!

 

Glad you found the solution after all that man! Was the car in an accident my chance? I know you said you took off the fender and some pieces? Did you add the grey looking silicone around the windshield or was it like that because it doesn't look very factory. I wonder the diapers you mentioned could they be factory sound deadaning?

 

I don't know if it was in an accident, but this was not related to an accident or fender replacement.

The issue was simply water leaking in mostly from the side where you see the grey silicone. I know it doesn't look pretty, but I had to isolate all the cracks. It cleans off easily.

One of the diapers/pads is on the rear of the left side panel by your left foot where the hood release and gas release are. It is not thick enough for sound deadening in my opinion.

I asked Honda for a discount on a Ridgeline for all my troubles. They said that they don't give discounts. .

 

Glad you fixed it!! Seems like a one off but great post none the less. Cant go wrong with a ridgeline for sure.. but its missing that leather! lol